Safety standards require that heavy duty vehicles such as used in construction and mining employ alarms for indicating reversing movement of the vehicle. Such alarms are controlled by the vehicle transmission shifting apparatus wherein a clearly audible and distinctive alarm signal is emitted to warn personnel of the reverse movement of the vehicle.
Such reversing alarms are subjected to high abuse and stringent duty cycles, and must be capable of dependable operation under adverse weather conditions and the extensive vibration to which they are subjected by vehicle operation.
It is an object of the invention to provide a reverse alarm for vehicles which is of concise configuration, high strength construction, and capable of producing a high decibel warning signal.
It is a further object of the invention to provide a reversing alarm for vehicles utilizing a synthetic plastic housing and electronic circuitry wherein the alarm is weatherproof, and may be cleaned by steam or sprays without damage thereto.
A further object of the invention is to provide a reversing alarm for vehicles which may be economically manufactured and assembled, and wherein the alarm may be readily mounted upon the associated vehicle in either a vertical or horizontal orientation.
An additional object of the invention is to provide a reversing alarm for vehicles utilizing an electronic circuit wherein the circuit components are totally encapsulated within a dielectric waterproof potting compound protecting the circuitry from shorting or failure due to vibration.
In the practice of the invention the reversing alarm includes a molded synthetic plastic housing having a dish shaped cavity defined therein which includes a circular opening intersecting an exterior surface of the housing. The cavity is defined by a sidewall intersecting a sound reflective base facing the cavity opening, and the base is of such a configuration as to efficiently reflect sound vibrations axially received thereon.
A diaphragm mounting assembly is located within the housing cavity, and includes an inner end upon which a vibratable diaphragm or cone is mounted for spaced opposed relationship to the cavity base surface. The diaphragm mounting assembly also includes an outer end upon which a radial flange is defined which cooperates with the cavity opening and seals the same to function as a cavity cover. The diameter of the diaphragm mounting assembly is less than the diameter of the cavity whereby an annular air passage is defined between the assembly and the cavity sidewall, and ports defined in the assembly flange permit sound vibrations generated by the diaphragm to be reflected from the cavity base along the lateral portions of the assembly and through the flange ports.
Electronic circuit components which energize the motor for vibrating the diaphragm are located within a recess defined in the diaphragm mount assembly, and these components are encapsulated within a potting compound rendering the circuit waterproof, and the components mechanically supported against vibration. The diaphragm mounting assembly is assembled prior to being placed within the housing cavity, and upon the interconnection of wiring between the circuitry and the housing the assembly is placed within the cavity and bonded thereto wherein the assembly flange seals the housing opening, and engaging bracing and support structure located upon the assembly cooperating with complementary shaped recesses and abutments within the housing cavity provide mechanical support for the diaphragm mounting assembly.
The housing is provided with extensions having holes defined therein for receiving mounting bolts or fasteners, and the holes are disposed at 90.degree. to each other to permit either horizontal or vertical mounting of the alarm, and provide universal alarm mounting options.